When observing a comet please try to forget how bright you think the comet
should be, what it was when you last viewed it, what other observers think
it is or what the ephemeris says it should be.

The equations for the light curves of comets that are currently visible
use only the raw observations and should give a reasonable prediction for
the current brightness. If the comet has not yet been observed or has
gone from view a correction for aperture is included, so that telescopic
observers should expect the comet to be fainter than given by the equation.
The correction is about 0.033 per centimetre. Values for the r parameter
given in square brackets [ ] are assumed.

Comet 2P/Encke
was recovered by southern hemisphere observers in late June, but was
only visible for a couple of weeks. It was a little fainter than expected
and faded from 7th to 10th mag.

This was the comet's 58th observed return to perihelion since its
discovery by Mechain in 1786. The orbit is quite stable, and with a
period of 3.3 years apparitions repeat on a 10 year cycle. This year
the comet was best seen from the southern hemisphere as an evening
object (it was not observable from the UK at all). The comet reached
perihelion in late May and made a relatively close approach to the
earth around July 4, when it was 0.19 AU distant and moved at over 5 degrees
per day. There is some evidence for a secular fading, and
observations at this favourable return will be important to confirm
this. Another suggestion is that Encke has two active regions, an
old one with declining activity, which operates prior to perihelion
and a recently activated one present after perihelion. The comet is
the progenitor of the Taurid meteor complex and may be associated
with several Apollo asteroids.

Comet 29P/Schwassmann-Wachmann 1
is now emerging from solar conjunction. In February and early March the comet
was in outburst, peaking at around 12th mag. It was not seen in
April, but returned to visibility in early May, rising to 12th mag
late in the month. I observed it at 13.7: on May 12.95 with the
Northumberland 0.30-m refractor. On May 29.97 it was 12.0: in my
0.20-m T x 75, dia 1.8', DC3. Andrew Pearce reports glimpsing it
at around 14th mag in his 0.41-m reflector at the end of December.

This annual comet has frequent outbursts and seems to be more often
active than not, though it rarely gets brighter than 12m. In early
1996 it was in outburst for several months. The randomly spaced
outbursts may be due to a thermal heat wave propagating into the
nucleus and triggering sublimation of CO inside the comet. It is
observable in Virgo for the rest of the year.
This comet is an ideal target for those equipped
with CCDs and it should be observed at every opportunity.

Comet 43P/Wolf-Harrington is
visible in the morning sky at around 13th
mag. I observed it on September 9.14 in my 0.20-m SC, making it
13.4:, dia 0.9' and DC2. On October 10.17 it was a weakly condensed
diffuse glow in the 0.30-m refractor x170, DC2, diameter 1.0'. On
November 4.2 it was 12.6 in the 0.30-m refractor. It is
now becoming too low for easy observation from the UK.

This is the ninth observed return of the comet, which was discovered
in 1924, then lost until 1951. The comet is in a chaotic orbit, and
made a close approach to Jupiter in 1936 which reduced its perihelion
distance from 2.4 to 1.6 AU. At the last return the comet reached
13m and this time round it could do a little better at 11m - 12m.
The comet is a morning object and remains at a similar magnitude
throughout the apparition. It will emerge from the summer twilight
in early August and the solar elongation continues to slowly increase
throughout the apparition, but the comet also moves southwards. It
is past its brightest but should remain visible
until the end of the year. Southern hemisphere observers should be
able to follow it for a few more months as it approaches opposition
and slowly fades.

Comet 46P/Wirtanen is no longer
visible at this apparition. It peaked at around 10th mag in March.

The comet is in a chaotic orbit, and its perihelion distance was much
reduced due to approaches to Jupiter in 1972 and 84. It has been
reported to outburst, but BAA data suggests that it has just been
rejuvenated after the perihelion distance was reduced. It is a
target for the Rosetta mission. A December perihelion would give a
close approach to the Earth, however the present period is exactly
5.5 years so that perihelia alternate between March and September.

Comet 65P/Gunn is a little
brighter than expected at 13.5. I observed it with a 0.20-m SC on
September 6.09 and made it 13.5:, dia 0.8', DC3. It is now too faint
for visual observation.

The comet was discovered in 1970 after a perturbation by Jupiter in
1965 had reduced the perihelion distance from 3.39 to 2.44 AU. In
1980 two prediscovery images were found on Palomar plates taken in
1954. The comet can be followed all round the orbit as it has a
relatively low eccentricity of 0.32.

Comet 78P/Gehrels 2 is also a little
brighter than expected. On November 4.2 it was 13.0 in the 0.30-m refractor.
Observing in very transparent conditions on November 21.95 I estimated it at
13.6 in the same instrument x170. It is currently at its brightest.

81P/Wild 2 is a new comet that made a very close (0.006 AU) approach
to Jupiter in 1974. Prior to this it was in a 40 year orbit that had
perihelion at 5 AU and aphelion at 25 AU. The Stardust spacecraft is
due to visit it in 2004 and recover material for return to earth in
2006. Only a few observations were made at the last return in 1991,
when it was 13m. This return was better and the comet peaked at around 10th
mag in March.

Comet 103P/Hartley 2
is now at its brightest. An
observation on October 4 made it 13.5 and a further observation on
October 7.8 with 0.33-m L approximately 13.0. By October 21.7 it had brightened
to 12.6, but was very diffuse and difficult to see. At the end of the month,
on October 31.76 it had reached mag 10.8 in my 0.33-m Lx100, but was DC2, dia 2.7'.
An observation in moonlight on November 10.77 put it at 10.6:, still very diffuse.
On November 22.75 it had reached 9.9 in the same instrument. By November 30th it
had become a little more condensed and was mag 9.5. Observations in early December
put it at 9th magnitude and a binocular object.

In 1982 the comet made a close approach to Jupiter, and it was
discovered by Hartley four years later, around nine months after
perihelion. It was accidently recovered by T V Kryachko of Majdanak,
USSR, on 1991 July 9.85, returning 5.6 days earlier than predicted.
It was well observed by the section at this return and observations
showed that the brightness peaked around 13 days after perihelion.
This return is also a good one and for the northern hemisphere it is
likely to be the brightest predicted periodic comet of the year. It
is an evening object throughout the apparition and slowly brightens
reaching 9m in late December when it is at perihelion. It will
then slowly fade, but should remain observable until April. The
orbit comes close to that of the Earth and it could produce a meteor
shower at the descending node in November. Calculations by Harold
Ridley gave a radiant of 19h56m +14ø, some 5ø Nf Altair, with a
likely maximum around November 17.
See also information from the IMO

Comet 1995 O1 Hale-Bopp
is now a morning object for observers south of the equator, and it has
faded below naked eye visibility.
It was a 'great comet', though in some ways comet Hyakutake made a
greater impression with its long straight gas tail.

Recent observations
show a dramatic fade of about 1 mag starting around October 20, which is
well shown in this lightcurve . The comet
is now near 7th mag.

This analysis of the
comet's light
curve, coma diameter and tail length was made for the TA special supplement on
the comet which was published in the autumn.
Over the entire apparition the comet has the corrected light curve:
-0.70 + 5 log d + 7.57 log r
There are significant variations from this, and the comet is currently nearly
a magnitude fainter than indicated by this equation.

1996 J1 Evans-Drinkwater
was discovered on UK Schmidt plates. Although reported as 16 mag at
discovery, a visual observation put it at 13.5 and it could have reached 9th
mag at perihelion, though it was very poorly placed for observation. The
comet was recovered on CCD images following conjunction and was
anomolously bright with a companion and seemed to have split. It is now too
faint for observation. Michael Drinkwater is an ex PhD student at the
Institute of Astronomy.

1997 D1 Mueller
A new comet was discovered on plates taken by Jean Mueller for the
2nd Palomar Sky Survey with the 1.2m Oschin Schmidt Camera on Feb
17th. The object was reported as 16th mag, but appeared brighter to
visual observers. The comet has become difficult to see because it is
very diffuse. An observation on October 10.16 with the Northumberland
refractor put it at 13.8, DC1, diameter 0.5'. An observation with the same
instrument x170 on November 21.97 made it a difficult 13.8. On December 1.0 it
was easier to see and had a starlike stellar nucleus, with total mag 13.2, DC s3.
If the light curve holds (which it doesn't seem to be)
it would peak at around 11th mag in December, however anything brighter than
13th mag seems unlikely.

Observations received so far (40) give an uncorrected preliminary light curve of
9.5 + 5 log d + [5] log r
though this is a very poor fit.

It became visible to amateur observers towards the end of the
year at 13th mag. It is a morning object and brightens rapidly as heads
towards a relatively close approach to the earth in mid January, when
it may reach 8m. Intrinsically it is quite a faint comet and by the
time it reaches perihelion at the end of February will be over 1 AU
from the earth, so it will not put on as good a show as is expected
from the meteors it has produced.

1997 G1 P/Montani
was announced on IAUC 6622. It is a 19th mag object discovered by
Joe Montani of the Spacewatch team. It is a distant object, with a
perihelion distance of 4.3 AU and will not become any brighter.
1997 G2 Montani
was announced on IAUC 6626. It is an 18th mag object, again reported
by Joe Montani of the Spacewatch team. The comet is predicted to
brighten to 16th mag at perihelion in April next year, but is at high
southern declination. It is possible that visual observation could
make it around 12th magnitude at that time, as visual observers often
find comets brighter than CCD estimates.
1997 H1 130P/McNaught-Hughes
has been recovered by Jim Scotti with the 0.9-m Spacewatch telescope
and by A Nakamura with the Kuma Kogen Astronomical Observatory 0.6-m
f6 Ritchey-Chretien telescope. The comet was first seen in 1991 and
the orbit is updated on IAUC 6640. The comet is unlikely to get much
brighter than 18th mag.
1997 H2 SOHO
discovered a new comet on April 29. It was expected to fade rapidly
and no visual observations were reported.
1997 J1 Mueller
Jean Mueller discovered a 13th mag comet with the Palomar Schmidt in early
May. It didn't get much brighter and is now too faint for visual observation.

1997 J2 Meunier-Dupouy
French amateur Michel Meunier reported a comet 6' SW of 1997 J1 on
May 7.9, moving more slowly and perhaps 0.5 mag brighter.
Independently another pair of French amateurs P Dupouy and J F
Lahitte reported it the next day.

On September 22.87 I made it
12.1 in my 0.33-m L x100, DC2, diameter 0.9', however it was quite
a difficult object to see. Using the Northumberland refractor (0.30-m,
f18) on October 4.8 I made it 13.0 (comets are usually fainter with
this instrument than with shorter focal length instruments). On
October 7.8 it was an easy object in my 0.33-m L at 12.3. On October
10.20 it was a difficult object in the dawn sky in the Thorrowgood
0.20-m refractor x140 at mag 12.7:, DC3, diameter 0.8'. Easier than
103P it is still moderately difficult to see. On October 21.7 I made
it 12.1 in my 0.33-m L x100, DC3 suggesting there is little change in
the brightness over the past month. On November 30.8 it was 11.6.

Observations received so far (145) give an uncorrected preliminary light curve of
4.2 + 5 log d + 8.8 log r
Observations are fairly well
scattered, but if the light curve holds it will peak at around 11th mag
in December and be visible until the end of 1998.

1997 K2
T. Makinen, Finnish Meteorological Institute, Helsinki; and
J.-L. Bertaux, Service d'Aeronomie, Verrieres-le-Buisson, reported
for the SWAN team the probable discovery of a comet from its
hydrogen Lyman-alpha emission appearing on full-sky images
(wavelength range 10-180 nm) taken from the SOHO spacecraft during
May-July 1997. The first image was on May 20.88 and
the resolution is 1 square degree. The discovery was made by
Makinen in the course of a complete survey of visible comets in the
SWAN images during Jan. 1996-June 1998. The appearance was
comparable to that of comet C/1997 O1 (Tilbrook) in SWAN images
during 1997 June 17-Sept. 6, suggesting that m_1 was roughly 10-12.
Peak Lyman-alpha intensity values (in Rayleighs) for C/1997 K2 were:
June 5.0 UT, 10.4; 7.4, 12.9; 13.1, 12.3; 14.8, 14.7; 24.5, 17.9;
26.6, 17.9; 28.7, 17.4. The object increased in extent from 2 deg
x 2 deg to 6 deg x 4 deg during this time. [IAUC 7327, 1999 December 4]

The SWAN instrument is a Finnish - French collaboration designed to study lyman alpha
emission in the 115 - 180 nm band. It has a 5x5 array of pixels with 1 degree
resolution and can image the entire sky. The sensor has imaged: 46P/Wirtanen,
45P/Honda-Mrkos-Pajdusakova, 1995 O1 (Hale-Bopp), 1995 Y1 (Hyakutake),
1996 B2 (Hyakutake), 1996 Q1 (Tabur) and 1997 O1 (Tilbrook)

1997 L1 Zhu-Balam
J Zhu reported observations of 5 objects detected on June 4 by the
Beijing Astronomical Observatory 0.6-m Schmidt during a search
program. D D Balam of Victoria noted that one of them was clearly
cometary with the 1.8-m reflector of the Dominion Astrophysical
Observatory.
The comet is 17th mag and was at perihelion in 1996 and will fade.
The comet was originally named Xinglong and thought to be a main belt
asteroid, but was renamed in 1998 [IAUC 6811, 1998 January 23] after
the discoverer and the person who pointed out that the object was
cometary.
1997 L2 SOHO
discovered another new faint sun approaching comet on June 10,
however this one was not a member of the Kreutz group. It is
expected to fade rapidly and is unlikely to be seen visually.
1997 M2 131P/Mueller
Japanese observers A Sugie and A Nakamura have independently
recovered comet Mueller 2 with 0.60-m reflectors and CCDs. The comet
was around 19th mag.
1997 N1 Tabur
Vello Tabur of Wanniassa, ACT, Australia discovered a 10th mag comet with his
0.20-m f5 reflector on July 3. The comet was weakly condensed with a 1.5'
diameter coma. There was some evidence that the comet was becoming more
diffuse and disintegrating as it approached perihelion, suggesting that it
wouldn't survive perihelion passage. I attempted observation of it on
September 7.84 and September 8.84 with the 0.20-m refractor and suspected an
object of around 9.5 - 10.0, and again suspected an object of 11.8 on
September 22.82, however no other confirming observations have been made.

Asteroid 1997 MD10
is on a cometary orbit. It has a very eccentric orbit, with a
period of 124 years, reaching perihelion at 1.5 AU in November.
Currently 18th mag and 2 AU from the Sun it is expected to fade because its
distance from the Earth is increasing. It is possible that it may grow a coma
as it gets closer to perihelion or it may be one of the many extinct Halley
type comets that are expected on dynamical grounds.
1997 N2 132P/Helin-Roman-Alu 2
was recovered by Carl Hergenrother using a CCD camera on the SAO 1.2m
reflector on Mt Hopkins. The comet was around 20th mag and nearly stellar.
The correction to the predicted elements was -0.6 day.
1997 O1 Tilbrook
Jason Tilbrook, Clare, S Australia discovered a 10th mag comet on
July 22 with his 0.20-m reflector. The comet is diffuse with a 2'
diameter coma. The comet will fade and is now too close to the sun
to observe.

1997 P2 Spacewatch. The
automated search program on the Spacewatch telescope discovered a
19th mag comet on August 12. It is a distant object and will not
become brighter than 18th mag. The orbit given on MPEC 1997-Q02 is
strongly hyperbolic and is only exceeded by comet Bowell 1980 E1
which was also perturbed by Jupiter. The comet passed within 1 AU of
Jupiter at the beginning of February this year.
1997 T1 Utsunomiya
Syogo Utsunomiya of Azamihara, Minami-Oguni cho, Aso-gun, Kumamoto-ken, Japan
visually discovered a mag 10.5 comet, strongly condensed with a 2' coma diameter
using 25x150B on October 3.6. [IAUC 6751, 1997 October 5].
The comet will fade as the distance from earth increases, although
perihelion is not until December. The comet should have been brighter than 12th mag
throughout September and may be visible on patrol photographs. Gabriel Oksa
observed the comet on October 6.80, estimating it at 9.8, diameter 3' and DC 3 in
20x80B. I was able to observe it on October 7.84, making it 9.8 in my 0.33-m L,
DC3, diameter 1.1' with a 2' tail in pa 113. A CCD image by Roderick Willstrop
with his 3MT showed a strong central condensation and prominent tail as does
this image by Denis Buczynski on October 8.09.
Vince Tuboly observing on October 8.8 made
the comet 10.5 in his 0.30-m reflector, with a 6', DC2 coma. My latest observation
on October 21.7 made it 9.3 in my 0.33-m L x60. Martin Mobberley recorded
this image on the same date. On November 1.80 I made
it 9.9 in the same instrument. An observation in moonlight with the N'land refractor
on November 10.75 put it at 11.5, but an observation with the reflector at the end
of the month put it at 10.4. It will soon be too low in the twilight for observation
from the UK.

1997 T3 Lagerkvist-Carsenty
Uri Carsenty and Andreas Nathues, of the DLR Institute of Planetary Exploration,
Berlin discovered a 19th mag cometary object on October 5.1 during the course
of the Uppsala-DLR Trojan Survey, in collaboration with C-I Lagerkvist, S Mottola
and G Hahn. [IAUC 6754, 1997 October 7].
It is in a distant elliptical orbit with a period of 19.7 years and will not become any
brighter. The comet was not named until January 1998, when it was named after the
discoverer and person who found that it was a cometary object [IAUC 6811, 1998 January
23]
1997 V1 P/Larsen
Jeff Larsen discovered a 17th mag comet on images taken with the 0.91-m Spacewatch telescope
at Kitt Peak on November 3.2. [IAUC 6767, 1997 November 3].
It is a distant, periodic comet with a period of 10.8 years and will fade.
1997 X2 134P/Kowal-Vavrova
Jim Scotti recovered the comet with the Spacewatch telescope at Kitt Peak on December 5.5
when it was 22nd mag. The predicted ephemeris required a correction of +5.3 days.
[IAUC 6784, 1997 December 10]